#region Copyright & License

//
// Copyright 2001-2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#endregion

using System;
using log4net.Core;

namespace log4net.Filter {
  /// <summary>
  /// Simple filter to match a string an event property
  /// </summary>
  /// <remarks>
  /// <para>
  /// Simple filter to match a string in the value for a
  /// specific event property
  /// </para>
  /// </remarks>
  /// <author>Nicko Cadell</author>
  public class PropertyFilter : StringMatchFilter {
    #region Member Variables

    /// <summary>
    /// The key to use to lookup the string from the event properties
    /// </summary>
    string m_key;

    #endregion

    #region Constructors

    #endregion

    /// <summary>
    /// The key to lookup in the event properties and then match against.
    /// </summary>
    /// <remarks>
    /// <para>
    /// The key name to use to lookup in the properties map of the
    /// <see cref="LoggingEvent"/>. The match will be performed against 
    /// the value of this property if it exists.
    /// </para>
    /// </remarks>
    public string Key {
      get { return m_key; }
      set { m_key = value; }
    }

    #region Override implementation of FilterSkeleton

    /// <summary>
    /// Check if this filter should allow the event to be logged
    /// </summary>
    /// <param name="loggingEvent">the event being logged</param>
    /// <returns>see remarks</returns>
    /// <remarks>
    /// <para>
    /// The event property for the <see cref="Key"/> is matched against 
    /// the <see cref="StringMatchFilter.StringToMatch"/>.
    /// If the <see cref="StringMatchFilter.StringToMatch"/> occurs as a substring within
    /// the property value then a match will have occurred. If no match occurs
    /// this function will return <see cref="FilterDecision.Neutral"/>
    /// allowing other filters to check the event. If a match occurs then
    /// the value of <see cref="StringMatchFilter.AcceptOnMatch"/> is checked. If it is
    /// true then <see cref="FilterDecision.Accept"/> is returned otherwise
    /// <see cref="FilterDecision.Deny"/> is returned.
    /// </para>
    /// </remarks>
    public override FilterDecision Decide(LoggingEvent loggingEvent) {
      if (loggingEvent == null)
        throw new ArgumentNullException("loggingEvent");

      // Check if we have a key to lookup the event property value with
      if (m_key == null) // We cannot filter so allow the filter chain
        // to continue processing
        return FilterDecision.Neutral;

      // Lookup the string to match in from the properties using 
      // the key specified.
      object msgObj = loggingEvent.LookupProperty(m_key);

      // Use an ObjectRenderer to convert the property value to a string
      string msg = loggingEvent.Repository.RendererMap.FindAndRender(msgObj);

      // Check if we have been setup to filter
      if (msg == null || (m_stringToMatch == null && m_regexToMatch == null))
        // We cannot filter so allow the filter chain
        // to continue processing
        return FilterDecision.Neutral;

      // Firstly check if we are matching using a regex
      if (m_regexToMatch != null) {
        // Check the regex
        if (m_regexToMatch.Match(msg).Success == false) // No match, continue processing
          return FilterDecision.Neutral;

        // we've got a match
        if (m_acceptOnMatch)
          return FilterDecision.Accept;
        return FilterDecision.Deny;
      } else if (m_stringToMatch != null) {
        // Check substring match
        if (msg.IndexOf(m_stringToMatch) == -1) // No match, continue processing
          return FilterDecision.Neutral;

        // we've got a match
        if (m_acceptOnMatch)
          return FilterDecision.Accept;
        return FilterDecision.Deny;
      }
      return FilterDecision.Neutral;
    }

    #endregion
  }
}